With the rapid development and progress of laser photoelectric technology, biomedical imaging technology combined with photoelectric technology will become a promising new industry in the future. For example, some new breakthrough has been made by research on biomedical cells imaging or by laser beams as a therapeutic tool. In the past ten years, the performance of pulse width, pulse energy and pulse wavelength tunable range of pulsed laser are greatly improved, and therefore the overall stability and easy operation in the ultra-short pulse laser system are highly improved. Prospective applications such as laser surgery (Photodisruption), photodynamic therapy and optogenetics, have also been developed in the biomedical field. In order to provide more complete and accurate biomedical image information, three-dimensional detection technology has become a trial and trend of current development.
At present, a noninvasive, non-destructive optical imaging technology in biomedical imaging observation or industrial inspection related fields includes digital holographic microscope photography, confocal laser microscopy, nonlinear optical microscopy.
Ultrafast camera, such as streak camera, has the fastest imaging speed, a single frame up to several picoseconds, and time interval between the images is up to hundreds of picoseconds. This technique can't reach the femtosecond time scale, and can only obtain light intensity information with low spatial resolution. It can't achieve full field wavefront detection mechanism. In pulsed laser microscopy, pulsed beam has ultra-short time window characteristics, so it can be used for ultrafast detection. However, only the light intensity detection can't achieve the full field wavefront detection.
In addition, in the ultrafast pulsed digital holography, combining the pulse ultra-short time window characteristics with digital holographic recording scheme, it mostly only provides a single pulse laser recording, and the time interval is limited by image sensor. The partially multiplexing mechanism needs to be adjusted by complicate angle and interference coherence matching, so that it is difficult to adjust the time, and difficult to apply.
Currently, most of the ultrafast optical detection technologies proposed in the world are mainly based on the detection of light intensity images, which may refer to the United States patent application number US, 2004/0190134, A1 and the U.S. Pat. No. 7,224,828 B2. Although this method can detect ultra-short time window characteristics of pulse beam source, it can't detect and analyze the full beam wave information. In addition, there is a drawback in this method that it is impossible to detect several pulses information at the same time, so that time interval of detection is limited by the image sensor, and it can't achieve the goal of ultrafast time analysis.
In the field of ultrafast digital holography, Prof. Hayasaki, et al. propose the use of ultrashort pulsed light source in digital holographic photography to achieve ultrafast full field wavefront detection. It used to observe the response as pulse laser applied to materials, achieving the mechanism of femtosecond window observation and detecting the linear and nonlinear optical phenomena. However, the same single pulse detection problem makes its time interval never to fulfill the mechanism of ultrafast time resolution. In this case, Prof. Zhai disclosed in the 2006 International Journal Optics Letters that the spatial multiplexing mechanism enables multiple pulse recording and detection in single detection. However, the complex spatial angle multiplexing system leads to difficultly adjust in time analysis of different time dimension such that such technology is limited to laboratory and not easy to promote.
In addition, in Chinese patent application number CN 204129432 U, CN 102841498, CN101763019B, the scheme of these patents can't be used for full field wavefront detection.
Thus, there are many shortcomings in conventional method of measurement. It is necessary to develop a novel digital image analysis technique to solve and overcome the above problems.